toilets and hutch

I have 2 8month old rabbits (bunnie & clyde) they live outdoors and have a wonderful hutch to sleep in with plenty of space.. and have been litter trained.. but recently they have been pooping and peeing in their bed area and not using the litter tray which is in the a corner in the longest part of the hutch, where it has always been since i've had them (2 months) i'v now had to put in a normal size litter tray and their corner tray in the bed area to keep it clean, because until then they jus do it all over their bedding in which i'm having to replace every day instead of every 3/4 days like the rest of the hutch and not only that its having to be scrubbed and washed due to the smell and attracting little hardback critters.

they dont do any pooping or weeing in any other area of the hutch and when i put the trays in the bigger part they just knock it over and empty it all over the hutch and carry on pooping and weeing in the bed area..

any ideas how i can get them to go back to the area where they used to do it so they have a sheltered area for sleeping wi all the room they have before!

sorry not much advice, what sex are they, and have they been neutered?

are they spending all their time in their hutch?